The present invention relates to a transadmittance amplifier.
The invention further relates to a corresponding transadmittance-transimpedance amplifier, a corresponding optical receiver, a corresponding method and a corresponding design structure.
Transadmittance amplifiers, which can be also denoted as transconductance amplifiers, are circuits that generate an output current that is a function of the difference between two input voltages.
Transadmittance amplifiers are e.g. widely used in optical receivers, in particular in variable gain amplifiers (VGA) of optical receivers. The VGA of an optical receiver has the function to amplify the output signal of the transimpedance amplifier (TIA) which has converted the photo current into a voltage. More particularly, the VGA should provide enough swing for a subsequent comparator stage to resolve the analog signal in the given cycle time.
Furthermore, the VGA should provide enough gain with high bandwidth to avoid additional intersymbol interference (ISI).